Method of pointing bolts



1m 29 w23. y www@ J. CRAIG.

Memor: cF Pom'rmc Bours.

FILED JUNE 6. 1921. 2 SHEETS-sneu' 2 Fammi.,

,Tanne onere, or serrait, rnnnsvnv'anra.

METHOD OF PONTING BOLES.

Application tiled .lune 6, w21,

whom it may concern.'

l t l, l; CRAIG, residi f ot vldutler and citizen et' the d or discovered niproveinents in s, ot which improvements the owing 1.. specification. i My inventionrela-tes to machining olf bolts and more. particularly to the turning oit pointed ends upon bolts. llolts are Ytorn/red L'roin rolled stock from which ordi narily lengths ot material are sheared, and it reqnisite'to 'li' in lr' a. cutting opera# tion a point upon thesh t 'ed-oil length ot stock or upon the blanlr otherwise prepared. he objects of my invention simplicity of structure and adequ v und economy in operation. ln the sequel it will appear that my invention is found not in apparatus merely, but also in a method of eilecting the desired cut.

ln this application l shall claim the method described. ln a companion application iiled November 2e, i922, Serial No. 602959 l claim as my invention the apparatus. i

ln a third application filed ldarch 18th, i921, Serial lilo. 583964, an application still pendingciv in the latent Orlce, l have de.- s iibed and claimed a bolt-pointing machine or 'the sainev general character as that to which my present invention is addressed. is characteristic ot that machine and of the machine of my present invention also thaJ the bolt under treatment is rolled in a slot termed by and `between opposite parallel cylindrical surfaces, the Width of the slot being equal to the diameter of the bolt blank. @ne these tivo surfaces is stationary, the other is movable, rotating on the common axis et the tivo'cylindrical surfaces. lt will be understood that, it a cylindrical article be so rolled between plane sur't'aces which extend parallel one to the other, the rate at which the rolled article Will advance will be exactly hall the .rate of relative movement of' the two surfaces; but it will V.further be understood that, when the rolling is between cylindri surfaces, the rat-e advance ot the rolled article will not bei exactly halt the surface' speed et the moving cylindrical surface. rlhere is a new factor introduced, namely, the difference in radius curvature of' the tivo surfaces, in consequence vol" which (in the machine of t nods or Serial No. 475,289.

vances, and it will be understood from WhatA has justl been said that there must be a niceness oi yadjustment ot relative speeds, to bring it about .that the cutter shall advance in exact synchronism with the bolt blank.

ln'tlieA machine ot my present invention l elinnate the necessity of minutely adjustlipv `he rate ot advance ol' the cutter, to accord vexactly Withthe rate ot' advance of the blank. l cause the cutter to advance at exactly half the speed of the movingcylin der and, adopting` a cutter of the particular construction presently vtoV be described, I taln advantage of the difference in 'the rate of advance ot cutter and, or' bolt blank, to etlect Y the cutting operation.

ln the accompanying drawings, Figure l is a view ot the machine of my present invention seen in end elevation, certain parts being tor the salie of clearness. broken awa-y; Figure ll is a. vieiv ot' the machine partly in side elevation', partly in medial an'dfvertical section; and Figures lll vand lV are diagrammatic illustrations of the manner in which cutting` is effected, in which manner oit cutting,- the improvement in method'particularly resides. A y

n a shaft l, suitably mounted and rotated from a sutable source ort power, is integrally carried a. drum At an interval from and opposite the periphery of drum 2, a stationary block 3 is mounted. vThis block presents to drum 2 a concave cylindrical tace, and its curvature is concentric with respect to the cylindrical face ot drumfthe interval at which drum 2 and block 3 stand apart (an interval equal to the diameter ol the bolt to :be pointed) may be nicely adjusted by securing block 3 ito a standard 4 by bolts 5, and formingl in Ablocks 3 radially extending slots 6 through which the securing bolts extend. rlhis standard (which as presently Will appear ser-ves other and `additional purposes) is arranged opposite drumv 24 at one side and atan interval from drum 2. lt stands as `shown in Figure ll to rearward 01" drum 2 on the right.

l() yeffected,

Shaft 1 -extends through an` opening in this standard. yAs shown in Figurel the peripheral extent of block f3 around drum 2 Aamountsto approximately 1800. The angu- I lar extent of this blockv is'liowever not l will, inyorderv to make possible the desired i to blocki `Accordingly, each complete rotasl adjustment, be'coniposed of sections. l

The space between. drum 2 and block S constitutes a slot a.; in this instance it is semicircumferentia-l in its extent. When the machine is assembled itwill be understood that abolt introducedvinto'this slot and lying in a line parallel'with the axis of rotation (that isv to say, longitudinally of the drum) will be ,siinultaneously tangent to the opposite faces of drum and of block.'v lt` will further be understood that rotation of drum`2 within the stationary vblock 3 will cause a" bolt` so lyingbetween, to roll` As the bolt rolls, it will advance along theslotin the direction inl which ythe drum turns, and from what has gonebefore itf,will'` bejunderstood that the rate of bolt advance relativelyv to rblock 3 will bey slightly less than one-half ythe rate at whichthe surfaceof Vdrum 2 turns relatively tion of drum 2 will effect the advance of the bolt something less than half way round the drum; or, if the slot extends exactly half way round the drum, then it will require a little more than one complete rotation of the drum to cause a bolt blank to advance throughout the entire length of the slot.

Loosely mounted lfor free turning upon` shaft 1 but` secure against longitudinal movement upon the shaft, is the cutter wheel 12, It isarranged to rearward, that is to say on theright-hand side (Fig. Il) of drum 2,.

The hub v'l' of the cutter'wlieel is prolonged I and extends freely through the opening in standard'e.- This cutter wheel 12 is caused to rotate in the v,same direction with drum 2 and at half thefspeed of drum 2 byv gearing interposed between shaft 1 and hub i', this gearing beingindicated at 8, 9, 10, and-,11.

The cutter wheel 12 carries the cutter 13, its cutting edge -ctas appears in Figure I) extends .1 vat oncelongitudinally of and transversely of the slot a, and (as appears in Figure Il) longitudinally of the cylindrical surfaces which define ther slot ct. ln other words, it is oblique `both tothe radius and to bolt, is .an v ascertainable the axis ofthe cylindrical surfaces. Furthermore, as willV appear in they uppermost presentation in Figure Il, there is clearance inthe formation of this knife 13 fromfits vcutting edge rearward, that is to the right.

ypairs of outwardly'extending yielding ngers 17. When the parts are assembled the arrangement is such that, as the machine operates, vfingers 17 .carry a bolt blank laid upon them intoslot a at the very instant when the forward end of the cutter blade comes `opposite the vend ofthe slot. This relative position is indicated in Fig. I on the right, where a blank Z is shown just entering the slot d', while the knife appears in` such `position thatthe forward end b of its cutting edge also is comingv opposite the end of slot o.. .immediately-upon entering slot a the bolt blank d engaged by the oppositevsur-rk facesr'of drum and block is retardedand advances.' at'reduced and definitely` controlled speed. The 1'?, borne as they are by drum' 2 at una nninishedspeed, swing aside, and, advancing, passbeyond contact with, the bolt blank. When'they have so passed they resume their normal position, ready to pick up another bolt blank on thenext rotation.

lnasniuch as vdrum 2 travels at twice the speed of the cutters, there will ordinarily be half as many pairs of lingers 17 upon drum 2 astherel are cutters upon wheel 12. The drawingsy show fourvcutters arranged at quadrant points about thewheel 12, and ycor-v d respondingly .two `pairs of fingers 1? arf What may be the value of this difference,

ranged diametrically opposite one another.y

lt remains to beremarked. that there isv no movement of the "cutters in a' direction per` pendicular to the plane of their orbit; there is no swinging of the lcutters in their carrier;

Athe cutter wheel and the parts whichit carries advance as aninteger. ln this respect the machine of this application differsfrom the machine of my application.l Serial No.

453,264, alluded to above. find it should in;` this connection'be `remembered `that there is no longitudinal movement of theibolt under treatment, no feeding Iof it forward toward,

cutting` edge of theknife is inclinedto the axis of the holt; that a portion -onlyof the cutting edge engages the work at any-given moment; and? that this work-engaging .p0ri tion progresses from end to end "of the obliouely set edge. y.

Operation is; as follows: The parts being l assembled as shown in Figures l and Il, the direction of rotation of vdrum 2 and-ofwheel ifiao,

l2 is anti-clockwise (ci. lilig. l) and the speed ot' rotation et drum f2 is as has already been made plain twice the speed of rotation oi wheel l2. ein unpointed bolt is laid on the ngers l? approaching the right hand end oi' tne slot. Rotation ot shaft l carries the bolt into the slot where immediately it begins .its rolling advance, traveling at something less than halt the speed at which the surface of drum 2 turns, and at something less than the speed which the cutters 13 advance. iks has been said, lingers i7, advancing ifaster than the blank d, swing aside, and pass beyond.

Considering now the cutting operation more minutely, and beginning with the parts in the posi ion shown at the right in Figure il, it will be seen that the cutting edge -c et the knife is coming into engagement with the end of the blank (l. should have been ekplainedabove that the blank Z when applied is brought accurately to position projecting from drum 2 to the rightfllig. Y.ll-an exactly predetermined distance. And it should further be said that this distance does not change. There is in lthe operation oiI the machine as shown no advance oi the blank longitudinally of the cylindrical sur- 'l'ace throughout the operation.) is operation progresses, the knife overtakes the blank; and, compassing the three positions shown somewhat diagrammatically in Figure l, arranged quadrant points, it will be seen that in the coin e ot the advance ot the blank throughout the extent oi' its semicircular path a the whole length ot the knii'e passes across the diametrical width of the blank. @n the right, the kr le is rearward oit' the blank. @n the lett, the blank is rearward of' tie knife, while at the intermediate point above, the knife wholly overlies the blank.

Turning now to Figure lill of the drawings, the line c-f will indicate the pos tion of the cutting edge ot the knife relatively to the blank d at the moment when the blank enters the slot a. Presently the edge ot the knife will overlie the blank on the line g-Jt, and it will be observed that in this position a cut is being formed which extends from the center to the perimeter ot the blank. .its operation progresses, the edge of the litnite will advance so that t-he line ot cut will come progressively to the positions indicated by the lines k-J, ma, o-gx The line upon which the cut is progressing then advances with the operation from the center of turning toward the perimeter; and meanwhile the clearance alluded to above in lt will be observed that the point 7" has developed, and this point now .lies within the under cut at the edge oi the knife. Cutting is progressing on so much oi the line c-Z as is indicated This line ot cut 'iw-J always entends to the periphery of the blank, and diminishes in length, until at the completion of the operation it is Zero. rllhe region x-y of actual Contact, of diminishing length, as already explained, is, as operation progresses, constantly advancing along the knife edge in the direction indicated by the arrow in Fig. lV.

lt will immediately be apparent to the engineer that minute shaping ot the knife edge makes possible minute gradation in the shape of the point which is cut. This point may be rounded,-a shape which ordinarily is advantageous.

l do not mean to limit myself to details ot structure, nor to details of machine operation. ln these respects the foregoing specilication is exemplary merely. lt is maniliest that the invention is applicable, not to the pointing oil bolts merely, but generally to the pointing et spindle-shaped articles.

l claim as my invention:

l. The method herein described of pointing a spindle-shaped article which consists in causing the article to rotate on its aXis under a knife whose edge extends in a line oblique to the axis of rotation and causing the line ot engagement between article and knife to advance as operation progresses longitudinally of the knife edge and to recede from the center toward the perimeter ofin the article.

2. The method herein described of pointing a spindle-shaped article which consists in spinning the article upon its axis under a knife edge set oblique to the axis of the spinning' article and, as cutting progresses, shifting the positionl o' article to cutter both longitudinally oi and transversely of the knife edge.

ln testimony whereof l have hereunto set my hand.

JAMES CBAlG 

